1. Field of the Invention
This invention relates to method and apparatus for displaying a three-dimensional picture.
2. Description of Related Art
A server computer, as a central information processing apparatus, and a client computer, as a user terminal information processing apparatus, maybe interconnected using a cable, a telephone line or a network, for purveying the information in the server computer to the user client computer, or retrieving the information in the server computer from the user client computer, It is recently practiced to represent the virtual reality three-dimensionally, as a conceptual model or metaphoric representation for information purveying services on a display device of the client computer which is capable of displaying graphics. Thus the user is able to use or retrieve the information purveying services in a form similar to reality.
Specifically, a variety of objects or equipments, such as desks, shelves, television receivers or doors, exist in the virtual reality. The user points the direction of movement in the three-dimensional virtual reality, using a pointing device, such as a mouse, trackball or a keypad, and moves within the displayed three-dimensional virtual reality for acting on the objects or the equipments within the three-dimensional virtual reality.
When the user moves in the three-dimensional virtual reality, he or she is free to move in an optional direction. Thus it is difficult for the user to realize in which direction he or she is to move or which objects or equipments will be encountered.
On the other hand, since the three-dimensional virtual reality is represented on a two-dimensional display device, that is a CRT display, it is difficult to reflect the intention of a producer who has produced the three-dimensional virtual reality.
If the user has moved to a position in the three-dimensional virtual reality not intended by the producer, the field of view of the user becomes incomprehensible such that he or she is unable to realize in which direction he or she is to move next.